Thermostat, or no thermostat?

[lodilobo]

This forum has impressed me over the past couple years with the knowledge of some of the members, and has helped me several times. Based on that, I have to ask the question......why would you need a thermostat in a 1/4 mile race car? I am asking opinions due to a disagreement I'm having with a long time friend, who is very "old school". So am I.....to a certain extent. But my opinion is based on actual experience......I didn't use a thermostat or restrictor in a high 9 second car for the past 2 seasons. The water temp. never exceeded 185. Then, when I had the intake off, and had a new thermostat sitting on a shelf, I said "why not.....it couldn't hurt." Well.... I was wrong. This week at test/tune, after one pass, my water temp. hit 250, and was quickly approaching 300. Thermostat stuck! Needless to say, I quickly removed it and gave it to my buddy who has been telling me for years......" you have to have a thermostat." Somebody....agree with me, or show me proof that I'm wrong. Thanks in advance for the input.

[dlotraf33]

Simple as "If it Works, Don't Fix It." On a drag only car I see no need, some may have other opinions. Part of problem is quality of some parts, I did the same thing and it wasnt a cheap thermostat, didn't open till 245 deg. You know where that one went. JMO...........

[sg4356]

On a drag car you do not need a thermostat, but if you are running the electric wtr. pump during a pass as most do, you do need a restriction plate. just to slow the wtr. down so the rad. can have time to cool the wtr.

[kitz]

Well a stuck thermostat is not going to work in any application. Your experiment is thus incomplete. Having said that though the 'If it's working don't fix it' makes sense to me.

I don't know about the restrictor. The heat transfer is a strong function of the convection coefficient of the coolant which improves with fluid velocity in general. I have never studied an automotive radiator in detail; it could be that difference in velocity without the restrictor is not a huge factor. There's another experiment for you though.

Kitz

[lodilobo]

No...actually the experiment was completed, resulting in the conclusion that there were no known negative affects of not using a thermostat, but very negative affects can occur when using a thermostat, if it becomes defective. I don't know much about the heat transfer, but the coolant, being water, maintained a reasonable temperature with no thermostat in place. However, some may argue that with no restriction, the water is circulating too fast to adequately cool the motor. Therefore, the water temerature reading with no thermostat in place, is meaningless. My response to that would be...while the water may be circulating faster, by maintaining a reasonable temperature, and always being present in the motor, the block temperature is not increasing significantly, or the water temperature reading would also increase.

[Mikej]

Nascar use tape to control temp. A street car may never get to operating temp without a thermostat. Using no thermostat or a restrictor, engine temp would very, depending on ambeint temp. Race engine would proably need more flow than the thermostat can provide. High RPM for an extended period of time.